CAJ | 학술논문

颗粒挥发性可以影响颗粒在大气中的寿命,对大气颗粒物中二次气溶胶的形成机制研究有一定的参考价值。以往研究测量颗粒挥发性采用的是热熔蚀器,其活性炭吸附器一旦老化后,在较高温度下可能会释放出活性炭,造成测量失真。本研究针对热熔蚀器的上述缺点,以稀释器替代活性炭吸附器部分,与单颗粒气溶胶质谱仪( SPAMS)连接,建立了一种在线分析单个气溶胶颗粒挥发性的测量方法。气溶胶颗粒分别通过两个通道进入SPAMS分析颗粒信息。通道1,气溶胶颗粒由管路进入加热器,被加热至不同的温度,颗粒挥发产生的气体和挥发后的颗粒内核进入稀释器部分,利用干净干燥冷的稀释气对加热挥发后的气体和颗粒进行稀释,使颗粒温度降低并短时间内不与气体发生冷凝,最后进入SPAMS进行检测。通道2为单独硅胶管,其长度与通道1相同,气溶胶颗粒通过通道2直接进入SPAMS检测。通过对比通道1和通道2获得的颗粒信息(粒径、数目和质谱信息等),得到气溶胶颗粒在不同温度下的挥发性。实验室用标准物质进行评估测试,结果表明,采用稀释器可以避免活性炭吸附器使用时间变长而失效,防止挥发性物质冷凝回到颗粒中。应用本方法初步测定了广州市春季气溶胶的挥发性,表明春季气溶胶多为高度挥发性和中度挥发性物质。
과립휘발성가이영향과립재대기중적수명,대대기과립물중이차기용효적형성궤제연구유일정적삼고개치。이왕연구측량과립휘발성채용적시열용식기,기활성탄흡부기일단노화후,재교고온도하가능회석방출활성탄,조성측량실진。본연구침대열용식기적상술결점,이희석기체대활성탄흡부기부분,여단과립기용효질보의( SPAMS)련접,건립료일충재선분석단개기용효과립휘발성적측량방법。기용효과립분별통과량개통도진입SPAMS분석과립신식。통도1,기용효과립유관로진입가열기,피가열지불동적온도,과립휘발산생적기체화휘발후적과립내핵진입희석기부분,이용간정간조랭적희석기대가열휘발후적기체화과립진행희석,사과립온도강저병단시간내불여기체발생냉응,최후진입SPAMS진행검측。통도2위단독규효관,기장도여통도1상동,기용효과립통과통도2직접진입SPAMS검측。통과대비통도1화통도2획득적과립신식(립경、수목화질보신식등),득도기용효과립재불동온도하적휘발성。실험실용표준물질진행평고측시,결과표명,채용희석기가이피면활성탄흡부기사용시간변장이실효,방지휘발성물질냉응회도과립중。응용본방법초보측정료엄주시춘계기용효적휘발성,표명춘계기용효다위고도휘발성화중도휘발성물질。
Volatility can influence the lifetime of particles in the atmosphere, and provide useful information on the formation of secondary aerosol. The previous studies generally utilized thermodenuder ( TD ) to investigate the volatility behavior of particles. Using TD, semivolatile species are vaporized at different temperature, and the vaporized gas is adsorpted by activated charcoal. However, carbon might be emitted from activated charcoal under high temperature or activated charcoal ageing. In this study, a new method was developed for the measurement of particle volatility by coupling a thermodiluter system to an online single particle aerosol mass spectrometer ( SPAMS) . Aerosol particles were passed into two different channels, and then analyzed by SPAMS. Through Channel 1, aerosol particles were heated to different temperature by heating tube, then non-volatile particles and volatile gas entered into the diluter. After diluting and cooling by diluent air, the non-volatile particles were analyzed by SPAMS. Through Channel 2, aerosol particles were analyzed directly by SPAMS without the heating process. Particle volatility was obtained by comparing the information ( particle size, particle number and mass spectrum ) of particles through Channels 1 and 2. Laboratory tests showed that the diluter could avoid the re-condensation of volatiles to the particles. This developed method was applied in the real time measurement of individual particle volatility in the spring of Guangzhou. The results showed that these particles were primarily comprised of highly volatile and moderate volatile species.